The Thornton-Pickard Horizontal Reflex is a British-made plate camera of the early single-lens reflex era, designed for sheet film or glass plates and aimed at serious amateur and professional users of its day. It is a wood-bodied reflex camera produced by Thornton-Pickard Manufacturing Co., a Manchester-based maker active from the late 19th century into the early 20th century.

Sales evidence for the Horizontal Reflex is very thin: a single UK auction hammer result from August 2024 saw an example sell for £60, which sets the only firm reference point for what one is worth in today's market. Because this is a wholesale saleroom figure rather than a retail price, dealer asking prices for clean, complete examples can sit higher, and condition-sensitive factors such as bellows integrity, shutter function and original lens presence will drive where any individual camera sells for.